I'm assuming you're talking about CPAP?

I didn't tolerate it. I tried for four months, and I never got used to it. I'm claustrophobic anyway and wearing the mask didn't help matters much. I couldn't handle the nasal one either. So I gave it up and never have gone back to using it.

Honestly, I didn't really see or feel a difference between using CPAP and not using it. I think I maybe lost about 10 lbs but otherwise I don't think it had any real effect. Your mileage may very.